public ParkingHomePage()
        {
            InitializeComponent();

            Title = "Home";

            //list parking spots
            CarparksListView.RefreshCommand = new Command(async() =>
            {
                await RefreshData();

                CarparksListView.IsRefreshing = false;
            });

            start.Clicked += (s, e) =>
            {
                infoLabel.Text = "Determining location...";
                var message = new StartTaskMessage();
                MessagingCenter.Send(message, "StartTaskMessage");
            };

            stop.Clicked += (s, e) =>
            {
                var message = new StopTaskMessage();
                MessagingCenter.Send(message, "StopTaskMessage");
            };

            HandleReceivedMessages();
        }
        protected override async void OnAppearing()
        {
            base.OnAppearing();

            //stops the background process
            var message = new StopTaskMessage();

            MessagingCenter.Send(message, "StopTaskMessage");
        }